There has been a longstanding need for antimicrobial agents having improved antimicrobial efficacy and improved speed of action. The specific requirements for such agents vary according to the intended application (e.g., sanitizer, disinfectant, sterilant, aseptic packaging treatment, etc.) and the applicable public health requirements. For example, as set out in Germicidal and Detergent Sanitizing Action of Disinfectants, Official Methods of Analysis of the Association of Official Analytical Chemists, paragraph 960.09 and applicable sections, 15th Edition, 1990 (EPA Guideline 91-2), a sanitizer should provide a 99.999% reduction (5-log order reduction) within 30 seconds at room temperature, 25±2° C., against several test organisms.
Many antimicrobial agents (e.g., iodophors, peracids, hypochlorites, chlorine dioxide, ozone, etc.) have a broad spectrum of antimicrobial properties. However, these agents sometimes have inadequate activity against bacterial spores, fungal spores, and fungi. This is particularly true under conditions requiring use of low level of such an agent, for example, to minimize corrosion of equipment or packaging, to provide adequate rinsing of a surface, to yield negligible residual antimicrobial agent, to minimize off-gassing of the antimicrobial agent, or to minimize chemical levels in the air. Killing, inactivating, or otherwise reducing the active population of bacterial spores and fungi on surfaces is particularly difficult. Bacterial spores have a unique chemical composition of spore layers that make them more resistant than vegetative bacteria to the antimicrobial effects of chemical and physical agents. Likewise, the unique chemical composition of fungal cells, especially mold spores, makes them more resistant to chemical and physical agents than are other microorganisms. This resistance can be particularly troublesome when the spores or fungi are located on surfaces such as food, food contact sites, ware, hospitals and veterinary facilities, surgical implements, and hospital and surgical linens and garments.
Control of the mold Chaetomium funicola, and of bacterial spore-forming microorganisms of the Bacillus species, can be especially important during food packaging, particularly during cold or hot aseptic filling of food and beverage products. Microorganisms of the Bacillus species include Bacillus cereus, Bacillus mycoides, Bacillus subtilis, Bacillus anthracis, and Bacillus thuringiensis. These latter microorganisms share many phenotypic properties, have a high level of chromosomal sequence similarity, and are known enterotoxin producers. Bacillus cereus is one of the most problematic because Bacillus cereus has been identified as possessing increased resistance to germicidal chemicals used to decontaminate environmental surfaces. For example, Blakistone et al., Efficacy of Oxonia Active Against Selected Sporeformers, Journal of Food Protection, Volume 62, pp.262-267, reported that Bacillus cereus was more tolerant of the effects of conventionally formulated peroxyacetic acid germicides than all other spore-forming bacteria tested, including other Bacillus and Clostridium species.
Bacillus cereus is frequently diagnosed as a cause of gastrointestinal disorders and has been suggested to be the cause of several food-borne illness outbreaks. Due to its rapid sporulating capacity, Bacillus cereus easily survives in the environment. Bacillus cereus is omnipresent in nature, and consequently can usually be found in animal feed and fodder. Bacillus cereus can contaminate raw milk via feces and soil, and can survive intestinal passage in cows and the pasteurization process.
Bacillus cereus is also known to cause serious human illness via environmental contamination. For example, Bacillus cereus is known to cause post-traumatic injury eye infections, which can result in visual impairment or loss of vision within 12-48 hours after infection. In addition, Bacillus cereus is regarded as transferable from washed surgical garments to patients.
Agents having greater or faster activity against bacterial spores, fungi, and other resistant microorganisms (particularly microorganisms of the Bacillus species) could help meet a substantial public health need, and one that is not adequately addressed by current commonly-used antimicrobial agents.